Extremism is quite sufficiently despicable in a singular form, but in multiplicity, as often is inclined to occur, becomes truly untenable. The roots of bigotry, zealotry, are truly simplistic, feelings of unnatural superiority or natural entitlement quite happily propagating from any number of quite innocuous stocks. All belief systems are inclined to pave the way for elitism, political hierarchies equally guilt rid, social formats liable to gentrification or class divisiveness. A quite reasonable argument could be made for fundamentalist, sectarianism being one of homo sapiens natural psychological defense mechanisms, self-preservation for self, family, and peers above all else. A sort of ensured continuance of generic and ethical material, generation upon generation, rather in direct defiance to the Darwinist principle of natural selection.
Historically, it is plainly obvious that dogmas are fleeting in the extreme, having to adapt constantly to try to keep pace with changing ideas and knowledge, to have any chance of relative longevity. The most deeply instilled of doctrines shimmy and shake in the bright lights of logic and reason, hence those most basic of entrenchments, piety, faith, are obliged to constantly renew, or revert, in the desire to retain some modicum of relevance.
The sworn blood enemy of extremism is of course inclusiveness, a much more wholesome dish to espy, taste and inwardly enjoy. Problematically, universal tolerance has by its very nature to incorporate all varieties, indeed vagaries, of thought, even the most unconscionable. The eternal downfall of the revolutionary triplet, ‘liberty, equality, fraternity, for all’, suggests the erroneous ability of lambs and lions to lay together in harmony. In the case of virulently held opinions, opposites do not counteract or cancel, bigotry is a wound that does not miraculously dissipate with an adequately expansive dressing of acceptance.
Irritation between components does not necessarily cause strife, rather such stimulation can lead to new, positively adapted organisms. In humanity effective irritation is communication. Simple conversation will capably resolve all ills.